In the control of internal combustion engines such as turbo-charged engines it has heretofore been suggested that a water heated plenum be associated with the intake manifold to facilitate warm up. It has also been suggested that the water heating be inhibited after warm up by providing a vacuum operated water valve controlled by a temperature switch.
The present invention is directed to an improved system which will function to inhibit the flow of heat to the intake manifold; which is relatively simple to manufacture; which can be preassembled for testing before placement in sealed condition; and which utilizes parts that can be manufactured at relatively low cost and be readily handled.
In accordance with the invention, a temperature controlled plenum valve is placed in the water line extending to or from the plenum associated with the intake manifold. The plenum valve comprises a plastic body including a base wall and a peripheral wall and a plastic cap including a base wall and a peripheral wall surrounding the peripheral wall of the plastic body. The peripheral wall of the base has a radially outwardly extending annular rib and the peripheral wall of the cap has a radially outwardly extending rib which are adapted to pass over one another to provide a snap fit during assembly. The base wall of said body having integral O-ring retainer for retaining an O-ring. A bi-metallic disc is positioned in the body within the confines of the peripheral wall of the body and normally engages the O-ring and is operable to engage the O-ring when the water temperature exceeds a predetermined amount.